fix: comprehensive audit fixes for dashboard and backend

Backend:
- Emit WebSocket events from REST delete/promote/demote handlers
- Emit DreamStarted/ConsolidationStarted from MCP tool dispatch
- Add path validation in backup_to() for defense-in-depth

Dashboard:
- Fix ConnectionDiscovered field names (source_id/target_id)
- Fix $effect → onMount in settings (prevents infinite loop)
- Fix $derived → $derived.by in RetentionCurve
- Fix field name mismatches in settings (nodesProcessed, etc.)
- Fix nested <button> → <span role="button"> in memories
- Fix unhandled Promise rejection in stats consolidation
- Add missing EVENT_TYPE_COLORS entries
- Add Three.js resource disposal and event listener cleanup
- Eliminate duplicate root page, redirect to /graph
- Update nav links and keyboard shortcuts to /graph

All 734+ tests passing, 22MB binary, zero build warnings.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/dashboard/build/_app/immutable/chunks/Dwpy08gq.js

@@ -0,0 +1 @@
+const e={fact:"#3b82f6",concept:"#8b5cf6",event:"#f59e0b",person:"#10b981",place:"#06b6d4",note:"#6b7280",pattern:"#ec4899",decision:"#ef4444"},o={MemoryCreated:"#10b981",MemoryUpdated:"#3b82f6",MemoryDeleted:"#ef4444",MemoryPromoted:"#22c55e",MemoryDemoted:"#f97316",SearchPerformed:"#6366f1",DreamStarted:"#8b5cf6",DreamProgress:"#7c3aed",DreamCompleted:"#a855f7",ConsolidationStarted:"#f59e0b",ConsolidationCompleted:"#f97316",RetentionDecayed:"#ef4444",ConnectionDiscovered:"#06b6d4",ActivationSpread:"#14b8a6",ImportanceScored:"#ec4899",Heartbeat:"#6b7280"};export{o as E,e as N};